Hollow charge warhead

ABSTRACT

A hollow charge warhead having an inert deflecting element embedded within said charge, said element being of a generally frusto-conical shape, the small basis of which being directed towards a punctiform detonator.

United States Patent Bodinaux HOLLOW CHARGE WARHEAD Inventor: GastonJean Olivier Bodinaux, Angleur,

Belgium Assignee: Les Ferges De ZeebruggeS.A., Herstal-leg- Liege,Belgium Filed: Dec. 4, 1969 Appl. No.: 882,045

Foreign Application Priority Data Oct. 27, 1969 Belgium ..PV 49639 US.Cl ..102/56, 102/24 Int. Cl ..F42b 13/10 Field of Search 102/ 24 BC, 56

[451 May 16, 1972 [56] References Cited UNITED STATES PATENTS 2,809,58510/1957 Moses ..102/24 I-lC 3,437,036 4/1969 Franzen et aL. ..102/24l-IC 3,451,339 6/1969 Precoul ..102/56 FOREIGN PATENTS OR APPLICATIONS1,220,306 6/1966 Germany l02/24 HC Primary ExaminerVerlin R. PendegrassAttorneyBacon & Thomas 57 ABSTRACT A hollow charge warhead having aninert deflecting element embedded within said charge, said element beingof a generally frusto-conical shape, the small basis of which beingdirected towards a punctiform detonator.

6 Claims, 4 Drawing Figures a: H V 4/ I29 HOLLOW CHARGE WARHEAD Thisinvention relates to a hollow charge rocket having a particularly highperforating power.

It is well known that the efficiency of a hollow charge depends on alarge number of parameters. In the present state of technics, neitherthe values of some of such parameters nor their interdependence may notalways be formulated rigorously. Accordingly, the research of optimumresults implies mandatorily a certain empiricism at a more or lessimportant extent according to the cases.

Thus, in the hollow charges with a liner, it has already been proposed(DAS 1,070,536) to embed, within the explosive charge and at closevicinity of the firing area, an inert lenticular screen for guiding thedetonating wave towards the periphery of the charge. However, suchinitially attractive solution has not resulted in satisfactory practicalresults and, consequently, it has not found a successful utility in thearmaments technics.

To overcome this drawback, it has been suggested to embed, within theexplosive charge, an inert revolution body of synthetic material, thiselement having a spherical area with rounded edges the smallest frontsurface of which lies in front of the liner tip at a distance therefromwhich is lower than the half-diameter of the caliber, the thickness ofsaid element being at least equal to 25 percent of the caliber diameter.Such disposition is namely described with details in the French Pat. No.1,457,972. It has given excellent results for heavy missiles, butpractical tests have demonstrated that most of its effects were lost forsmaller calibers, namely in rocket heads of 2.75 inch. As regards thelatter, there was presently no truly satisfactory solution. In fact,such known heads are able to pierce only blindages having a maximumthickness between about 150 and 200 mm under optimum conditions.

It is an object of the present invention to bring a solution to theproblem set by the efficiency of small size hollow charge heads. Theefficiency of the suggested solution will be appreciated in that, whenproceeding with test firings, blindages with a thickness of 450 mm havebeen regularly pierced, the penetration openings of the tips having onlya very small widening.

Such results are obtained according to the invention with a hollowcharge having a liner comprising one or several of the followingfeatures:

a. in the explosive charge, is embedded an element under the form of atruncated revolution body the large base of which is directed to theliner and the small base, towards a pin-point detonator;

b. the connecting surfaces between the conical surface of the saidelement and the bases thereof are torus-shaped surfaces;

c. the liner, the said element and the pin-point detonator are strictlycoaxial;

d. the distance between the large base of the said element and the tipof the said liner is at least equal to the halfcaliber size.

Preferably, the inner wall of the head casing will have, in front of theconical surface of the said element, a truncated length the top angle ofwhich is lower than that of the said conical surface of the element.

The intersection circle of the conical surface of the said element withthe plane of its large basis is advantageously situated in thecylindrical surface defined by the inner wall of the casing.

The minimum distance between the element and the inner wall of thecasing is of about one-fifteenth of the inner diame ter of the latter.

The thickness of the said element, i.e., the height of the resolutionbody, is preferably between the half inner diameter and the half outerdiameter or caliber size of the casing.

The characteristics of the invention will be more apparent by thefollowing description of a specific embodiment given by way ofinformation, reference being made to the enclosed drawings wherein:

FIG. 1 is a vertical section of a rocket according to the invention;

FIG. 2 shows the rock according to FIG. 1 in axial section;

FIG. 3 shows, on an enlarged scale, the head of the rocket illustratedin FIG. 2 and FIG. 4 shows the geometry of the hollow charge.

The rocket shown in FIG. 1 comprises a head 1 a motor 2 and spreadablefins 3.

The head 1 comprises a cylindrical tubular casing 4 on the front portionof which is fastened a hollow cap 5 the top of which is provided with apiezoelectric generator 6 operating at the impact. In the front portionof the casing, is disposed a conical metal liner 7 the top or tip 8 ofwhich is directed to the rear portion of the head and is situated asaccurately as possible on the axis of the said casing 4. This liner ishoused in a corresponding conical recess of a cylindrical explosivecharge 9. Within this charge, is embedded an element 10 describedhereafter. The basis of the said charge 9 opposite to that receiving theliner 7 is centrally provided with a truncated recess in which isinserted a pin-point detonator 11 which passes through a radial wall 12provided in the said casing.

Behind this wall, is provided a fuse 13 of any suitable type cooperatingwith the said piezoelectric generator 6.

The motor tube 2 contains a propellent charge 14 of the double base typeas well as a ballistic auxiliary means 15 applied on a rigid support 16.The charge 14 may be fired by means of a device shown diagrammaticallyin 17.

In its rear portion, the motor tube 2 is closed by a wall 18 supportingnozzles 19 as well as the pins 20 of the fins 3.

The detonator 11 is housed in a metallic case having a cylindricalportion 21 extended by a truncated portion 22. The length of portion 21is substantially equal to the thickness of wall 12.

This case contains a rapid combustion powder charge 23 housed in thesaid truncated portion 22 and extended within the said cylindricalportion 21 by a concavely flanked point 24. This point 24 surroundedwith a slower combustion powder charge 25 contacts the top of a conicalcharge 26 which is also of rapid powder. These various charges may bemade integral with each other by gluing.

This construction provides an accurate centering of the end of point 24on the axis of easing 4. The bottom of the said truncated portion 22 isparallel with the small base of element 10 at a very small distancetherefrom or even in contact therewith.

As previously disclosed, this element 10 has a large base 27 situated ina plane perpendicular to axis X-X of casing 4 and directed to the point8 of liner 7, a small base 28 directed to the detonator 11, a conicalsurface 29 and between the latter and the said bases, torus-shapedconnecting surfaces 30 and 31 respectively.

As indicated in dotted lines on FIG. 4, the extended conical surface 29intersects the plane of the large base 27 according to a circle situatedin the cylindrical surface defined by the inner wall 32 of casing 4.

The distance d separating the bases 27 and 28 is between the half innerdiameter a of the casing and the half outer diameter b of the latter orthe caliber size.

The minimum distance d from element 10 to wall 32 is of about a/ l 5.

The taper angle of surface 29 is slightly lower than that of liner 7which is equal to 60.

The curvature radii r and r of surfaces 30 and 31 respectively have eacha distinct value between 1 and 2 times d The distance d separating theface 27 from the point 8 is higher than b/2. If at., is the distancebetween the face 27 and the intersection point, with axis XX, of thetangent to surface 27 perpendicularly to the generatrix of liner 7 inthe plane of FIG. 4, the distance d;, will be preferably higher than 2.5X (1,, and lower than 6 X d,,.

Preferably, the inner surface 32 of the casing will have, in front ofsurface 29 of the element 10, a conical section indicated in 29 on FIG.4, the charge 9 being profiled correspondingly. As shown, walls 29 and29 are converging towards the plane of the said face 27.

The element may be made of any suitable synthetic material. However, itis preferably made of metal to prevent any distorsion as well under theacceleration effects as when the detonating wave is propagated.

With these arrangements, a detonating wave directed as perfectly aspossible as well as an optimum tip effect are obtained, thereby allowingthe outstanding performances initially mentioned. As regards fuse 13, itmay be of any suitable type. On FIG. 3, a suitable fuse has been shownwith some details. This fuse comprises an electric detonator 33 whichmay be energized by the piezoelectric element 6 via cable 34, saiddetonator 33 being carried on a slide 35 the shifting of which isallowed after the withdrawal of a locking rod 36. The withdrawal of saidrod 36 is effected through the intermediary of a retardation devicecomprising a stationary cylinder 37 containing microballs 38 permanentlyforced back by a piston 39 having a spring 40.

In the wall of cylinder 37, is provided an opening 41 allowing the saidballs 38 to escape provided this opening is uncovered. This is obtainedby the shifting of a sleeve 42 under the inertia effect.

The shifting of the sleeve 42 is controlled by a safety ring 43 which isunlocked by inertia at the start.

It is apparent that the above described embodiments may be variouslymodified within the scope of the invention.

What I claim is:

1. Hollow charge warhead having a tubular casing, a conical liner, anexplosive charge, a deflector embedded into said charge and a pin-pointdetonator, wherein:

a. the deflector is frusto-conical in shape, the large basic of whichfaces said liner and the small basis of which faces said detonator;

b. the axis of the conical liner, the deflector and the pinpointdetonator are coaxial;

c. a pin-point transfer passage is provided between said detonator andsaid deflector;

d. at least the connecting surface between the conical surface and thelarge basis of said deflector is curved, the radius of curvature beingat least equal to the shortest distance between said deflector and theinner surface of said casing;

e. the axial length of said deflector is at least equal to one fourth ofthe outer diameter ofsaid casing; and

f. the inner surface of said casing has a conical portion facing andpartly surrounding said deflector.

2. Hollow charge warhead according to claim 1, wherein the shortestdistance between said deflector and the inner surface of said casing isequal to approximately one-fifteenth of the inner diameter of saidcasing.

3. Hollow charge warhead according to claim 1, wherein the intersectioncircle of the conical surface and the plane of the large basis of saiddeflector lies with the cylindrical surface of the inner wall of saidcasing.

4. Hollow charge warhead according to claim 1, wherein the distancebetween the large basis ofsaid deflector and the apex of said conicalliner is at least equal to half the outer diameter of said casing.

5. Hollow charge warhead according to claim 1, wherein the axial lengthof said deflector is comprised between half the inner diameter and halfthe outer diameter of said casing.

6. Hollow charge warhead according to claim 1, wherein said pin-pointdetonator is housed in a metal case having a cylindrical sectionextended by frusto-conical section, the latter being seated in acorresponding recess of said explosive charge.

1. Hollow charge warhead having a tubular casing, a conical liner, anexplosive charge, a deflector embedded into said charge and a pin-pointdetonator, wherein: a. the deflector is frusto-conical in shape, thelarge basic of which faces said liner and the small basis of which facessaid detonator; b. the axis of the conical liner, the deflector and thepinpoint detonator are coaxial; c. a pin-point transfer passage isprovided between said detonator and said deflector; d. at least theconnecting surface between the conical surface and the large basis ofsaid deflector is curved, the radius of curvature being at least equalto the shortest distance between said deflector and the inner surface ofsaid casing; e. the axial length of said deflector is at least equal toone fourth of the outer diameter of said casing; and f. the innersurface of said casing has a conical portion facing and partlysurrounding said deflector.
 2. Hollow charge warhead according to claim1, wherein the shortest distance between said deflector and the innersurface of said casing is equal to approximately one-fifteenth of theinner diameter of said casing.
 3. Hollow charge warhead according toclaim 1, wherein the intersection circle of the conical surface and theplane of the large basis of said deflector lies with the cylindricalsurface of the inner wall of said casing.
 4. Hollow charge warheadaccording to claim 1, wherein the distance between the large basis ofsaid deflector and the apex of said conical liner is at least equal tohalf the outer diameter of said casing.
 5. Hollow charge warheadaccording to claim 1, wherein the axial length of said deflector iscomprised between half the inner diameter and half the outer diameter ofsaid casing.
 6. Hollow charge warhead according to claim 1, wherein saidpin-point detonator is housed in a metal case having a cylindricalsection extended by frusto-conical section, the latter being seated in acorresponding recess of said explosive charge.